1. Field of the Invention
This invention relates to the field of hydraulic transportation of coal or mineral slurries in large pipelines at high pressures over long distances.
More particularly, this invention relates to the transportation of coal slurries by the utilization of an inline, high efficiency axial flow pump in large pipelines at high pressures and over long distances.
2. Description of the Prior Art
A recent state-of-the-art search relative to slurry pumps did not disclose the use of an axial flow pump for transporting liquids containing solids in suspension.
Most pipeline slurry pump operations utilize either displacement pumps of the reciprocating type or centrifugal pumps. State-of-the-art piston pumps are of the high pressure, low capacity variety and multiple pumps in parallel are required, particularly where a large tonnage of coal is hydraulically transported through large pipelines to meet current energy demands. It is estimated 25 to 30 million tons of coal will be needed annually in the very near future.
A multiplicity in series of state-of-the-art moderate capacity, low pressure centrifugal pumps would be required to meet the needs heretofore mentioned.
The piston pump, then, is disadvantaged in that while it may be a high pressure pump it is low capacity; consequently, many in parallel are required to transport high volume slurries over long distances. Additionally, heavy duty piston pumps are very large in size and complex to incorporate into an existing pipeline.
The centrifugal pumps are disadvantaged in that while they have a moderate capacity they are generally low in pressure; thus, many are required in a series relationship to transport large volume slurries over long distances.
The present invention teaches the use of an axial slurry pump having high capacity, high pressure and a relatively small size that is positioned in line with an existing pipeline for efficient hydraulic transport of coal slurries and the like for long distances from remote mining areas to primary and secondary user stations, such as electric power, synthetic fuel and chemical plants. An axial pump concept is highly suited for pumping liquids containing solids in suspension, such as coal and mineral slurries. Since it characteristically has the highest flow rate per unit inlet flow area of any pump type, it will, therefore, have the smallest pump diameter for a given flow rate. The axial pump has the highest hydraulic efficiency of any bladed rotary pump because of its straightforward and simple hydraulic flow geometry which produces minimum flow losses.